Added Junit Testing

Author: rashi07dashore

src/main/java/com/thealgorithms/misc/ShuffleArray.java

@@ -1,6 +1,5 @@
 package com.thealgorithms.misc;
 import java.util.Random;
-import java.util.Scanner;
 /**
  * The Fisher-Yates (Knuth) Shuffle algorithm randomly permutes an array's
  * elements, ensuring each permutation is equally likely.
@@ -13,7 +12,7 @@
  *
  * This class provides a static method to shuffle an array in place.
  *
- * @author Your Name (https://github.com/Chiefpatwal)
+ * @author Rashi Dashore (https://github.com/rashi07dashore)
  */
 public final class ShuffleArray {
     // Prevent instantiation
@@ -33,32 +32,6 @@ public static void shuffle(int[] arr) {
             arr[j] = temp;
         }
     }
-    /**
-     * This method takes user input to create an array.
-     *
-     * @return the array created from user input
-     */
-    public static int[] getUserInputArray() {
-        Scanner scanner = new Scanner(System.in);
-        System.out.print("Enter the size of the array: ");
-        int size = scanner.nextInt();
-
-        int[] arr = new int[size];
-        System.out.println("Enter " + size + " elements:");
-        for (int i = 0; i < size; i++) {
-            arr[i] = scanner.nextInt();
-        }
-        return arr;
-    }
-    public static void main(String[] args) {
-        int[] userArray = getUserInputArray();
-        System.out.println("Original Array:");
-        printArray(userArray);
-
-        shuffle(userArray);
-        System.out.println("Shuffled Array:");
-        printArray(userArray);
-    }
     /**
      * This method prints the elements of the array.
      *

src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java

@@ -0,0 +1,107 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the ShuffleArray class.
+ * 
+ * @author Rashi Dashore (https://github.com/rashi07dashore)
+ */
+class ShuffleArrayTest {
+
+    /**
+     * Test for basic shuffling.
+     */
+    @Test
+    void testShuffleBasic() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int[] originalArr = arr.clone(); // Clone original array for comparison
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    /**
+     * Test for an edge case with a single element.
+     */
+    @Test
+    void testShuffleSingleElement() {
+        int[] arr = {1};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original
+        assertArrayEquals(originalArr, arr);
+    }
+
+    /**
+     * Test for an edge case with two elements.
+     */
+    @Test
+    void testShuffleTwoElements() {
+        int[] arr = {1, 2};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+        // Check that the shuffled array still contains the same elements
+        assertTrue(arr[0] == 1 || arr[0] == 2);
+        assertTrue(arr[1] == 1 || arr[1] == 2);
+    }
+
+    /**
+     * Test for an empty array.
+     */
+    @Test
+    void testShuffleEmptyArray() {
+        int[] arr = {};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original (still empty)
+        assertArrayEquals(originalArr, arr);
+    }
+
+    /**
+     * Test for large array.
+     */
+    @Test
+    void testShuffleLargeArray() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    /**
+     * Test to ensure all elements are present after shuffle.
+     */
+    @Test
+    void testShuffleRetainsElements() {
+        int[] arr = {1, 2, 3, 4, 5};
+        ShuffleArray.shuffle(arr);
+        
+        // Check that the shuffled array contains the same elements
+        assertTrue(arr.length == 5);
+        for (int i = 1; i <= 5; i++) {
+            assertTrue(contains(arr, i));
+        }
+    }
+
+    private boolean contains(int[] arr, int value) {
+        for (int num : arr) {
+            if (num == value) {
+                return true;
+            }
+        }
+        return false;
+    }
+}